System for information on demand

ABSTRACT

The present invention provides a system for serving information data such as video data to one or more users, comprising: one or more storage medium units for storing data of said information data; one or more end devices for receipt of said information data by the user; managing means for managing distribution of said data to said end device, the managing means being capable of receiving demand data form said user and related to data selected by the user in the end device, and which managing means output distribution control data including channel information of the selected information data and routs information from the end device; and least one ATM switch for connecting the storage medium unit, the end device and the managing means, and for routing the data from the storage medium unit and the distribution control data from the managing means.

BACKGROUND OF THE INVENTION

Conventional cable tv systems deliver video data from a distributioncompany through a cable to monitors of a number of viewers. Althoughnowadays many programs are distributed through many channels by eachcable tv company, the user or viewer has to wait until the desiredprogram is started and transmitted through a selected channel.

Recently, also interactive video systems have been proposed. In suchinteractive video system a viewer can chose a desired movie to bedisplayed on the monitor of said viewer. In such video-on-demand systema direct connection to the monitor or end device of a user isestablished, whereafter a demanded movie can be viewed by the end user.

In this known system it is however virtually impossible to upscale thesystem after it has been established e.g. by a distribution company.When the number of members for such a system increases and the number ofdemanded videos is increased, a new interactive video system has to bebuilt.

SUMMARY OF THE INVENTION

The present invention provides a system for serving information data toone or more end devices of one or more users, comprising:

one or more storage medium units for storing information data;

managing means for managing distribution of the information data to anyone of the end devices, wherein the managing means receive demand datarelating to information data selected by the user through his device,and wherein the managing means output distribution control dataincluding channel information of the selected information data androuting information for said end device; and

routing means for connecting the storage medium unit to the end device,and for routing the information data from the storage medium unit andthe distribution control data from the managing means.

This system according to the present invention provides a sort ofplatform and can operatively be connected to an end user through apublic network, can operate as a stand alone system operativelyconnected to end devices, in which latter case the system according tothe present invention is also provided with navigation devices forpresenting possible choices for an end user entering the system.

Preferably the routing means comprise at least one ATM switch. Thebasics and standards of ATM (Asynchronous Transfer Mode) are laid downin recommendations I.150 and I.327 as published in March 1993 by theInternational Telecommunication Union. ATM is generally used foraddressing a specific packet-oriented transfer mode which usesasynchronous time division multiplexing techniques. The multiplexedinformation flow is organized into blocks of fixed size, where saidblocks are referred to as cells. A cell consists of an information fieldand a header. The primary role of the header is to identify cellsbelonging to the same virtual channel within the asynchronous timedivision multiplex.

Preferably said information data is video and/or audio data although thepresent invention is not limited to this application. A system accordingto the present invention may also comprise applications for video-games,library functions, databanks etc., although a first promisingapplication field relates to video on demand services.

In case the information server system according to the present inventionis connected to a public network, the demand data preferably includes apublic address to be assigned to the selected information data.

Preferably the managing means provide program data for informationretrieval to the end device, so that an end device will be downloadedwith such program data from the system. This feature provides theadditional advantage that the end device only needs to include verylittle software for starting up purposes etc.

Although in a small scale configuration, such as in an hotelaccommodation or to like, the information services system according tothe present invention may comprise only one storage medium unit (andeven one end device), the system according to the present inventionpreferably comprises at least one second storage medium unit. In such acase the managing means comprise a table for storing data representinginformation data allocation to the first and second storage medium uniton basis of demand data from an end device. In this way the managingmeans manage the switching of the ATM switch for establishing virtualchannels between the end device and the storage medium unit.

Preferably the storage medium unit according to the present inventioncomprises;

memory means for storing video and/or audio data;

table means for memorizing data representing a relationship between therouting information and the video and/or audio data stored in thestorage means;

program memory means for storing program data for control of theoperation of the storage medium unit;

control means for controlling the memory means, the table means and theprogram memory means according to program data and for outputting one ormore control signals to the end device; and

at least one interface for transmitting the video and/or audio data withthe routing information and a control signal in the form of one or morepackets to the routing means and for receiving program data foroperation of the storage medium unit in the form of one or more packetsfrom the routing means. The memory means can comprise a magneto-optical(MO) disc or hard disc which is more agile than a MO disk. Also,preferably the routing information is supplied to the ATM interface ofthe storage medium unit.

Preferably the information server system in a video and/or audio dataapplication is capable of providing still mode, fast forwards mode,reverse mode, fast reverse mode as in VCR (video cassette recorder) anda mosaic mode operation.

To prevent time delay even in less agile memory means of the storagemedium unit, preferably video and/or audio data is divided in apredetermined number of data groups arranged in a sequence differentfrom the original sequence.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details, features and advantages of the present invention willbe described in the following referring to the next drawings with shelldiagrammatic representations of embodiments of the present invention,and wherein

FIG. 1 is a representation of an entire system for information ondemand;

FIG. 2 is a representation of a first embodiment of a storage mediumunit;

FIG. 3 is a representation of a second embodiment of a storage mediumunit;

FIG. 4 is a schematic representation of control and data flow in thestorage medium unit shown in FIGS. 2 and 3;

FIG. 5 is a representation of a third embodiment of a storage mediumunit;

FIG. 6 is a representation of a storage medium unit corresponding to thestorage medium unit shown in FIG. 2, with a resulting flow of datagroups;

FIG. 7 is a diagram of the timing of an ATM interface in the storagemedium unit;

FIG. 8 is a representation of an embodiment of the navigation systemshown in FIG. 1;

FIG. 9 is a representation of an embodiment of the end user device shownin FIG. 1;

FIG. 10 is a representation of an embodiment of the system manager shownin FIG. 1;

FIG. 11 is a diagram showing basic reproducing functions with staggeredrecording;

FIG. 12 is a diagram showing a mosaic menu function;

FIGS. 13, 14 and 14A show respective record formats of record tracks ona MO disc;

FIG. 15 shows a representation of reproduction of data recorded in astaggered format according to FIG. 14;

FIG. 16 shows an example of multicasting;

FIG. 17 is a diagram of an example of a sequence of communication stepsin a system according to the present invention; and

FIG. 18 is a diagram of another example of a sequence of communicationsteps in a preferred embodiment of the system according to the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following description in which reference is made to the figures,describes a combination of hardware and software; it should beunderstood that some hardware components may be combined into a singlehardware component such as a CPU where functions are time multiplexed.It should also be understood that connections between logic (software)units can be more complex than is shown schematically in the figures.

FIG. 1 shows an entire configuration of a preferred embodiment of aninteractive communication system according to the present invention,comprising: an ATM switch 1 (as example only: ForeRunner ™ ASX-200 ofFore Systems Inc., Warrendale, Pa., USA); storage medium units 20 (SMU);end devices 40; a system manager 60 and navigation devices 30. ATMswitch 1 connects the storage medium units 20, the end devices 40, thesystem manager 60 and the navigation devices 30 to each other,selectively, by using virtual channel connections and data istransferred to and from these components in a form of ATM packetsconsisting of a 5 byte cell header including routing information and a48 byte information field through ATM user/network interfaces providedbetween each device and ATM switch 1. ATM switch 1 has a conversiontable of routing information such as Virtual Channel Identifier and bychanging the routing information of each incoming ATM packet to therouting information designating the output virtual channel, the ATMpacket can be transferred to the correct destination. ATM switches areknown and further explanation is omitted here.

The interactive communication system will be explained below,specifically referring to the embodiment, where video-on-demand (VOD)service is supplied to users. It should, however, be noted here thatother applications, such as teleshopping, games and other types ofinformation exchange, are equally possible. Such services can bereferred to as information-on-demand services in general.

In the interactive communication system shown in FIG. 1 video signalsand/or audio signals are stored in SMU's 20. Several embodiments of aSMU 20 will be described below in detail.

In FIG. 1 end devices 40 are set top boxes, each of which cancommunicate with the navigation devices 30, the system manager 60 andcan decode video data (preferably compressed according to the MPEG-2standard) and/or audio data from a SMU 20, and supply decoded videosignal and/or audio signal to a monitor 43 and/or a speaker system 42.Each set top box or end device 40 has an input device 44, for example akeyboard or remote control, connected thereto. Preferably a set top boxis provided with a graphical processor unit 49 for generating graphicaldata to monitor 43 to facilitate interaction with the user. Preferablythe data for the graphical processing unit is supplied by the systemmanager through the ATM packets. A viewer can input instructions throughthe keyboard 44 or other suitable input device through the set top box40. An embodiment of a set top box 40 will be described below in detail.

Navigation devices 30 can provide information on available videoprograms to any one of the set top boxes 40. Such information can berepresented on the monitor 43 of the set top box 40 in a graphical wayor by text, or by a combination thereof. Available video programs arevideo programs which can be selected by a viewer. Such requestableinformation will hereinafter be referred to as service items. Anembodiment of a navigation device 30 is described below in more detail.

The system manager 60 manages operation of the interactive communicationsystem by managing the operation of the ATM switch 1. An embodiment ofthe system manager 60 will be described below in more detail.

A major feature of an interactive communication system according to thispreferred embodiment of the present invention is, that there are norestrictions on the hardware used or the operating system installed.Each set of communication operations is preceded by transmission of acontrol software program dedicated to such set of operations to areceiving and/or transmitting component, so that the receiving and/ortransmitting component can optimally handle the incoming and/or outgoingcommunication following this down-load of said control software program.

In the embodiment of FIG. 1, at least one of the SMU's 20 is an archiveSMU. In this embodiment the other SMU's 20 are delivery SMU's. Thearchive SMU stores many kinds of control software programs, video dataand/or audio data. An archive SMU may comprise as memory means a tape orMO disc, while a delivery SMU preferably comprises an agile hard disc orMO disc as memory means. A MO disc is less agile than a hard disc butmore agile than a tape. Each of the delivery SMU's stores separate partsof the data of the archive SMU. While the archive SMU may also be usedas a SMU for delivery purposes, the delivery SMU's are used for VODservice. The system manager 60 downloads control software program to thearchive SMU and the delivery SMU for a copy operation from the archiveSMU to one of the delivery SMU's at the beginning of or in advance of avideo on demand service. The installation of a delivery SMU by thearchive SMU is shown in more detail in FIG. 18. The delivery SMU storesnecessary video data from the archive SMU according to a command for thecopy operation from the system manager 60, and in particular from thestorage medium manager 62.

When the system manager 60 receives the demand data from an end device40, the system manager 60 outputs to the ATM switch 1 distributioncontrol data including information of virtual channels for the selectedvideo data produced from the received demand data and an address of theend device 40. Next, the delivery SMU outputs the selected video datawith the routing information for this end device 40. A software programfor write-in operation is down-loaded from the system manager 60 to theRAM 24 of the SMU 20 before copy operation of the video data isperformed. The CPU 22 of the SMU 20 controls write-in operation of thephysical storage medium, 21 according to the software program forwrite-in operation stored in the RAM 24. Then the software program forwrite-in operation in the RAM 24 is replaced with a software program forread-out operation by down-load from the system manager 60 before videoservice starts. The CPU 22 controls read-out operation of the physicalstorage medium 21 according to the software program for read-outoperation in video service.

The interactive communication system preferably comprises a plurality of(delivery) SMU's. In the system, the necessary video and/or audio dataof a particular video and/or audio program is only copied from thearchive SMU to one of the delivery SMU's, if the number of end devices40 with the possibility to select the particular video and/or audioprogram is smaller than a predetermined number. On the other hand, thenecessary video and/or audio data is also copied from the archive SMU orfrom the above delivery SMU to one or more of the other delivery SMU's,if more than the predetermined number of end devices have thepossibility to select the particular video or audio program. Thepredetermined number can be determined based on certain statistics orreal time monitoring of the number of end devices 40 requesting theparticular video and/or audio program at a specific point in time.

The preferred embodiment of the present invention provides for thepossibility that the number of end users is monitored in run time andthat the configuration will dynamically change to prevent the systemfrom overloading. When the number of end users increases, a new deliverySMU can be loaded from the archive SMU or another delivery SMU.

The system manager 60 preferably outputs backup control data, for thesituation that one of the delivery SMU's malfunctions. Selected videoand/or audio data is then output by another delivery SMU, which is notmalfunctioning and is selected according to said backup control data.The conversion table of virtual channels in the ATM switch 1 is updatedby the system manager 60 so that the input virtual channel of a possiblymalfunctioning delivery SMU is changed to the virtual channel of anotherdelivery SMU to provide the same video and/or audio data from the secondSMU.

A user selects the desired navigation service and connects the enddevice 40 to a navigation device 30 providing the desired navigationservice. Navigation data including a software program for displaying amenu of service items and identification data corresponding to eachservice item is downloaded preferably beforehand from at least onenavigation device 30 selected by the end device 40. The monitor 43 ofend device 40 displays such a menu of the available service items and,if necessary, corresponding identification data thereof. A menu fromnavigation device 30 may comprise video and/or audio information andcontrol data, either in graphical form, textual format or a combinationthereof, to facilitate the choice for the end user.

If a user selects a video and/or audio program through the input device44 from the menu by pointing the desired video program with a pointer inthe monitor 43 or by entering the identification data corresponding tothe desired program, if displayed on the monitor 43, the identificationdata is supplied to the system manager 60 by the end device 40 via ATMswitch 1. Such identification data may be a public address in case thatthe system manager 60 is connected to public ATM network. The navigationdata may further include video data obtained from SMU 20 or navigationdevice 30. The navigation data down-loaded from a navigation device 30can also contain information on other selectable navigation devices 30.

In a not shown embodiment an end device 40 can be connected to anavigation device through a public ATM switch, in which case such anavigation device can be selected through a public address. Through sucha public navigation device it would also be possible to choose othernavigation devices via the first publication navigation device.

The system manager 60 down-loads a VOD-software program for end devices40 corresponding to a selected video program to the end device 40, afterthe system manager 60 receives identification data from the set top box40. The system manager 60 also downloads a VOD-software program for theSMU's 20 corresponding to the selected video program to the SMU 20 viathe ATM switch 1, before VOD service starts. The system manager 60selects the SMU 20 and the most appropriate service items according todata representing video program allocation, for example in the form of atable, in the SMU's 20 and provides distribution control data includingthe information of the channel and the routing information correspondingto the selected video program to the selected SMU 20 so that the SMU 20operates to reproduce the selected video program.

A controller 26 in the SMU 20 controls the physical storage medium 21,so that the physical storage medium 21 reproduces selected video data ina play mode selected by the end device 40 as described below in moredetail. The reproduced video and/or audio data is supplied to ATMinterface 29.

As explained earlier the physical storage medium may comprise a harddisc, a MO disc or tape on which a video movie is recorded.

An ATM interface 29 combines the reproduced video 35 and/or audio datapreferably divided into cells each containing 48 bytes with the routinginformation stored in the memory of the SMU 20 in the form of ATMpackets and outputs the same to the ATM switch 1.

Control data from the controller 26 such as control information for theend device 40 is supplied to the end device via the ATM interface 29 andthe ATM switch 1. Control data from the end device 40 such as a requiredplay mode is received through the ATM switch 1 and the ATM interface 29.

The ATM switch 1 routes the ATM packets between the end devices 40, theSMU's 20 and the system manager 60 according to the routing informationattached to the ATM packets. The conversion table of the private ATMswitch 1 is updated by the system manager 60.

In the not shown embodiment wherein a public ATM switch is used incombination with the private ATM switch, the virtual channel connectionof the public ATM switch is established by using a public address at thestart of the service.

In VOD operation, an end device 40 outputs control data requesting aplay mode, such as normal play, fast forward play, reversed play, fastreversed play, still picture mode or more vague mode, to the ATM switch1 through an ATM interface 41 according to the mode selection on theinput device 44 by the user. The ATM switch 1 then routes the controldata to the system manager 60. The system manager 60 outputs controldata requesting the selected play mode to the ATM switch 1 through theATM interface. SMU 20 reproduces the selected video data in the selectedplay mode. As a variation, the control data requesting a play mode canbe routed from the end device 40 directly to the SMU 20.

In case of VCR options, the physical storage medium is preferably a harddisc, as such hard disc is more agile than the other mentioned physicalstorage mediums. As an alternative an MO-disk can be used, on whichinformation is recorded in a staggered fashion, which will be describedhereinafter.

The system manager 60 functionally comprises one or more storage mediummanagers 62, a storage medium group 63 including one or more serviceitem groups 64 and one or more service item providers 65, a servicerouting manager 66 and a program manager 67. Each storage medium manager62 may contain static data and/or dynamic data with respect to each SMU20 under its control. The static data may comprise for example type,costs or recording capacity of each storing medium unit 20. The dynamicdata may for example include status information such as whether or notthe SMU is occupied by video and/or audio data and whether or not it isbeing in use, or whether or not it is malfunctioning.

The storage medium group 63 outputs a request for assignment of a SMU 20to the storage medium manager 62 on basis of the requirements from theend devices 40. Such requirement can be specified by the statisticalinformation, such as potential number of the end devices 40 that canrequest service in a certain time frame or length of video program.Other possible requirements may be whether or not any end device 40 hasa possibility to select the more complex play mode such as mentionedabove and including fast forward, fast reverse etc. The storage mediummanager 62 proposes a suitable SMU 20 or suitable storage medium in theSMU 20 to a storage medium group 63 for the video service to the enddevice 40, according to static data and/or dynamic data with respect toeach SMU 20 contained therein, e.g. table means, and the request fromthe storage medium group 63. Further, storage medium group 63 controlsdown-load operation of software programs to one of the end devices 40 inresponse to a request from this end device 40.

In case of a plurality of storage medium managers 62, each storagemedium manager 62 may propose a suitable SMU 20 belonging to eachstorage medium manager 62 for the video service to the storage mediumgroup 63. A storage medium manager 62 will ask another storage mediummanager 62 to propose a suitable SMU 20, requested by the storage mediumgroup 63, if said storage medium manager 62 can not satisfy the requestof the storage medium group 63. More specifically, the service itemproviders 65 request assignment of one of the SMU 20 to the storagemedium manager 62 via the service item group 65. The service item group65 also control the down-load operation of control software programsoriginally provided from the program manager 67, which manages allcontrol software programs to be used in the system and delivers eachdevices updated, suitable, and effective programs.

The service item group 65 can down-load a suitable down-loadablesoftware program to the set top box according to the table thereinrepresenting relationship between service item identification andservice item provider. When the request is provided from the serviceitem provider, the service item group 65 can decide which down-loadablesoftware is suitable for subsequent operation of the set top boxaccording to the table in the service item group.

Even if the storage medium manager 62 is malfunctioning, themalfunctioning storage medium manager 62 may be restored while the SMU20 outputs video and/or audio data, as reproduced video and/or audiodata is directly output to the ATM switch 1 without routing by thestorage medium manager 62.

Next, full VCR functions, for example fast forward, reverse, fastreverse and still play mode will be explained. In the full VCR function,an agile storage medium, for example a hard disc, is used. The agilestorage medium is installed in one or more of the SMU's. At thebeginning of the video on demand service, the video and/or audio data ofthe selected video program or video program with possibilities of VCRfunctions from end device 40, is copied from the archive SMU or adelivery SMU to this agile storage medium. The agile storage mediumoutputs video and/or audio data in the play mode required by a set topbox 40 under control of the system manager 60. The system manager 60provides for changing the virtual channel, if the full VCR function isrequested by the end user, so that such end user is connected to an SMUwith a hard disc enabling the full VCR function through the virtualchannel. In the case, where an end device 40 is supplied withinformation from an MO-disc on which this information is recorded in astaggered fashion, and the end device for example request a fast forwardor fast reverse play mode, a separate SMU containing an agile hard disccan be employed. This may be advantageous, when time will lapse betweenthe request and the moment another virtual channel delivering this playmode becomes available. When the agile disc is employed intermediately,this agile hard disc can be engaged at a time pointer, corresponding tothe time pointer of the virtual channel in use at the time of therequest, can be speeded up or slowed down, and can consequently bedisengaged, when the time pointer and speed of the agile disc correspondto that of another virtual channel delivering information in theselected play mode from an MO-disc containing information recorded in aforward or reverse staggered fashion.

When a set top box 40 requires simple VCR functions such as stepwisefast forward mode or stepwise fast reverse mode, these simple VCRfunctions can be performed by another delivery SMU 20. In this case, thedelivery SMU which does not include an agile storage medium, for exampleoutputs video and/or audio data recorded in a certain format which willbe described hereinafter in a number of virtual channels through the ATMinterface with respective time delays between the virtual channels. ATMswitch 1 then provides the video and/or audio data in the required playmode to the set top box 40 by changing the relationship between inputvirtual channels and output virtual channels under control by the systemmanager 60.

Some examples of communications established between the end devices 40,the system manager 60 and the SMU's 20 by using the table data shown inFIG. 11 will be explained hereafter. If the end device 40 (STB-2)requests a selected movie by calling the identification number 678901corresponding to the movie and provided from one of the navigationdevices 30 at time 0:09, one of the service item providers 64 (SIP-1) isdesignated by the identification number.

The service item provider 64 (SIP-1) then checks the present time andobtains from the table therein the next available time point 0:10 as thestarting time of the movie, distribution control data including thenumber “2” designating the SMU 20 storing the video and/or audio data ifthe movie and the number “2” designating one of the service item streams(SIS) from the SMU 20 making the movie available from the beginning atthe time point 0:10, and the virtual channel number “21” for thisstream, and supplies the SMU 20 designated by the end number “2” withthe SIS number “2”, virtual channel number “21” and the end devicenumber “STB-2”.

The service item provider 64 (SIP-1) up-dates the conversion table inthe ATM switch 1 according to another table data available in theservice item provider 64 (SIP-1) so that the relationship between inputvirtual channel number “21”, for the service item stream (SIS) and theoutput virtual channel number “21” for the end device 40 (STB-2) isestablished. Therefore, the data stream of the requested movie isprovided to the end device 40 (STB-2) from the beginning at time 0:10.

If the end device 40 (STB-2) requests one of the service item providers64 (SIP-1) for full VCR function, the service item provider 64 (SIP-1)obtains from the table therein distribution control data including thenumber “4” designating the SMU 20 having full VCR function capabilityand the number “1” designating one of the service item streams (SIS)from the SMU 20 designated by the number “4” with the SIS number “1”,virtual channel number “28” and the end device number “STB-1”.

The service item provider 64 (SIP-1) up-dates the conversion table inthe ATM switch 1 according to another table data available in theservice item provider 64 (SIP-1) so that the relationship between inputvirtual channel number “28” for the service item stream (SIS) and theoutput virtual channel “7” for the end device 40 (STB-1) is established.Therefore, the data stream of the requested movie is provided to the enddevice 40 (STB-1) with full VCR function.

Such an interactive communication system as outlined above is suitableto be used as a platform for a plurality of server-owners, navigationdevice owners, system manager owners and users simultaneously, where oneparty can for example exploit one or several SMU's 20, as well as asystem manager 60 and/or one or several navigation devices 30.

In FIG. 1 the entire system is configured around a single ATM switch 1.Application of more than one private ATM switch and/or public ATMnetwork is equally possible. Furthermore, another type of transmissionnetwork can be used. The network with one or more ATM switches, however,is considered to be the most suitable network configuration for theapplications envisaged.

Next, details of each device will be explained.

FIG. 2 shows a configuration of a SMU 20. Each SMU 20 contains aphysical storage medium 21, for example an Magneto Optical (MO) disc anda corresponding driver or one or more hard discs and the correspondingdrivers thereof, an ATM interface 29 as part of the SMU 20 or locatedoutside such unit 20, a memory 25, for example for storing a table, anda controller 26 formed by a CPU 22, a RAM 24, a ROM 23, and a bus 27.

CPU 22 of controller 26 controls the storage medium 21 and otheroperations of the SMU 20 according to software programs stored in ROM 23and an additional control software program downloaded into RAM 24 andtable data stored in this memory of the SMU 20.

The physical storage medium 21 primary contains service items, but canalso contain control software program to be down-loaded to the enddevice 40 or one or more of the SMU's 20 when required.

ROM 23 of the SMU 20 preferably contains a microkernel operating systemand a storage medium interface resident software such as an ATM drive,an MO disc driver. The microkernel operating system functions as a basicset of instructions, capable only of the most elementary ofcommunication operations, e.g. down-load of control softwarespecifically tailored for subsequent communications to be performed bythe SMU 20. The ATM driver is used for establishing communicationsthrough the ATM interface 29. The MO disc driver is responsible for themode in which the physical storage medium 21 functions which will bedescribed hereinafter. The controller 26 also contains a table 25, inwhich relationships between virtual channels and end devices 40 areestablished.

The ATM interface 29 may communicate with the ATM switch 1 in a fullduplex mode, where the ATM interface 29 can simultaneously handleincoming and outgoing ATM packets 28. In FIG. 2 such an ATM packet 20 isshown to contain a header portion A, usually comprising five bytes, andan information field portion B, usually comprising forty-eight bytes.

RAM 24 contains executable code in ROM 23, a down-loadable module foroptimum functionality as a server, and a buffer.

FIG. 3 shows a SMU 20, where bus 27 is divided into a separate controlbus and a separate data bus to provide a high throughput.

FIG. 4 shows a schematic representation of control and data flow in theSMU 20 shown in FIG. 3. Here distinction is made between incoming andoutgoing video and/or audio data and incoming and outgoing control dataand incoming control software program to be down-loaded. Respectivepackets of video and/or audio data, control data and software program,even if these packets ate transferred to same SMU 20 or same end device40, should have different routing information in the header to bedistinguishable from each other.

FIG. 5 shows a third embodiment of the SMU 20, where an ATM switch 1 andthe ATM interface 29 of the SMU 20 are incorporated. As a resultconnections can be established from the SMU 20 directly through ATMinterfaces 41 to the end devices 40. In this case, the system manager 60may be connected to the ATM switch 1 or the controller 26 may replacethe function of the system manager 60.

FIG. 6 shows a SMU 20 corresponding to the embodiment of FIG. 2, wherethe method for reading and outputting data segments from a physicalstorage medium, e.g. a disc is shown. As an example data groups areoutput via three virtual channels, which channels could also be formedby separate physical channels. In this figure the principle ofreproducing staggered recording data, which will be further describedhereinafter, is shown. The SMU 20 shown here contains a buffer 210 and atimer 211, where the buffer 210 is preferably a part of the ATMinterface 29. The video data is divided in a predetermined number T ofsentences, where T corresponds to the number of channels and equalsthree in case of FIG. 6. Each sentence is divided in a predeterminednumber N of data groups and N equals four in case of FIG. 6. The videodata are recorded in the storage medium 21 after the order of the datagroups is changed in such a way that n-th (where n=1, 2, 3, 4 . . . N)data group of the first sentence is followed by n-th data group of theTth, T-1th, . . . , and T-(T-2)th sentences sequentially, as n issequentially increased, as shown in the upper left side of FIG. 6.

The video data recorded in the above manner is sequentially andcyclically reproduced from the storage medium 21. The n-th data groupsof the respective T sentences are sequentially stored in the buffer 210and output to respective different virtual channels through the ATMinterface 29. After respective N data groups of T sentences are output,the virtual channels are switched over in the next and following cyclesas shown in FIG. 7, so that N×T data groups are continuously reproducedvia each virtual channel with a time difference of one sentence fromeach other as shown in the right hand side of FIG. 6.

FIG. 8 shows a configuration of a navigation device 30. Navigationdevice 30 preferably comprises: a controller 36, formed by a CPU 32, aROM 33, a RAM 34 also for navigation software programs to be down-loadedto the end devices 40 and a bus 37; a table 35 for available videoprograms and identification data, for example a public address ofavailable video programs, and also an ATM interface 31. The controller36 controls operation of the navigation device 30 according to programsstored in ROM 33 and RAM 34. The navigation device 30 down-loadsnavigation software programs to the set top box 40, when the set top box40 requires a navigation operation to the navigation device 30. Thenavigation device 30 then provides information relating to availablevideo programs and identification data thereof to the set top box 40.Public addresses can be used when a public network is used in theinteractive communication system. Many kinds and versions of thenavigation menu can be provided, if the interactive communication systemhas a plurality of navigation devices 30, which handle for example aJapanese version, an English version, three dimensional graphicalversion etc.

FIG. 9 shows the configuration of an end device, here a set top box 40.The set top box 40 may comprise a CPU 45, a RAM 46, a ROM 47 and an MPEGdecoder 48. CPU 45 controls operation of the set top box 40 according toprograms stored in ROM 47 and RAM 46. Said programs may be down-loadedfrom the system manager 60, a SMU 20 or a navigation device 30. The MPEGdecoder 48 decodes compressed video data and/or audio data, supplied viathe ATM switch 1 and supplies video data, if necessary combined withdata from a graphic processor 49 through a video RAM memory 50 to themonitor 43 and supplies audio data via an amplifier 51 to the speakersystem 42. The CPU 45 produces demand data according to instruction datainput through the keyboard 44 or a similar device by the user. Suchdemand data is output via the ATM interface 41.

FIG. 10 shows a configuration of the system manager 60. The systemmanager 60 contains a CPU 68, a ROM 69, a RAM 70, and here a memory forvarious VOD software programs to be down-loaded to the set top boxes 40and/or the SMU's 20, an ATM interface 61 and memory 71, e.g. in the formof table means. The CPU 68 controls operation of the system manager 60.The system manager 60 provides operation software to SMU's 20 and settop boxes 40 and updates tables for data representing a relationshipbetween input virtual channels and output virtual channels in the ATMswitch 1. Such a system manager 60 can perform all functions describedabove relating to the storage medium manager 62, the program manager 67,the service item providers 64, the service item group 65 and the serverrouting manager 66.

FIG. 11 shows a sequence of scenes, where said sequence can beaccomplished by displaying video data on various transmission channels.In this example twelve (virtual) transmission channels are employed asT=12, though from channels 4 to 12 are omitted from the drawing forsimplification. Data groups are reproduced from a physical storagemedium 21 containing the staggered recording data and output via thesevirtual channels in a similar manner to FIGS. 6 and 7. As shown in FIG.11, the sequence of scenes can be altered by switching from channel tochannel for input of video data comprising such a scene so that a simpleVCR function can be realized. For example, by switching from channel 1to channel 2 while the scene ‘2’ is displayed, the scene ‘4’ can bedisplayed, thereby skipping scene ‘3’ as fast forward mode. Similarly,by switching from channel 3 to channel 1 while the scene ‘6’ isdisplayed, the scene ‘5’ will next be displayed thereby creating areverse mode. Such switching between virtual channels can be done byupdating the conversion table of the ATM switch 1 under control of thesystem manager 60 according to the control data from the end device 40.When switching between channels is not performed, the natural sequenceof scenes will be followed, as this is the sequence in which video dataoccurs on a single channel.

Scene 5 appeared after scene 6 by switching from channel 3 to channel 1.Thus reverse skip play is performed.

FIG. 12 shows an example of a mosaic function to be performed by an enddevice 40, whereby selected scenes taken from a sequence are displayedon monitor 43. A user can in this way select a starting point, otherthan the beginning of a film, by issuing a corresponding demand throughthe input device 44. Such a mosaic function can of course also be usedfor visualizing a menu of service items selectable through one orseveral navigation devices 3, e.g. title frames of several selectablevideo programs, where such selected scenes for mosaic function can bedisplayed by switching the virtual channels on a real time basis andstoring these into the video RAM 50 simultaneously or by reproducing thevideo data previously stored in the SMU 20 as mosaic video data. Next,recording formats of video data on a physical storage medium 21 will beexplained, referring to FIGS. 13-15.

In FIG. 13 a physical storage medium 21 is shown, where a head 90 isattached to an arm 91, movable to and from the center of the physicalstorage medium 21. Here, the physical storage medium 21 is formed by aMO disc. Data tracks of the MO disc 21 contain data groups in thestaggered recording sequence 92 shown in this FIG. 13 above the physicalstorage medium 21. The arrows above and beneath this representation ofsequence 92 denote the order, in which head 90 reads the data groupsfrom the physical storage medium 21. As shown here, reproducing head 90skips data groups on the outbound pass over the physical storage medium21, where the skipped data groups are read during the inbound pass overthe physical storage medium 21. In this way no time loss occurs betweenthe end and start of a sequence of data groups, to be sent to thecontroller 26 of the SMU 20 (see FIG. 6) and a continuous flow of datagroups in the order, required by the controller 26 of the SMU 20 isensured. Because of the continuous flow of data groups a buffer memoryof only a small size is required.

Video data, which is to be recorded in a storage medium with a formatdescribed above, is reproduced from said storage medium 21, and outputfrom the SMU 20 to the ATM switch 1 through the ATM interface 29 asthree virtual channels.

In FIG. 14 first and second video data with the same content butopposite time lines are recorded on the disc. In this case the datagroups of the first video data and the data groups of the second videodata are interleaved. The first video data is used, when the set top boxrequires normal forward, fast forward, or stepwise fast forward playmode. On the other hand, second video data is used when the set top boxrequires reverse play mode. Furthermore it is possible for the datagroups of the first video data to be recorded on every other track ofthe disc. The data groups of the second video data are stored inremaining tracks of the disc. Then the recorded first video data isreproduced from every other track of the disc by moving a reproducinghead in a first direction. Recorded second video data is reproduced fromthe remaining tracks of the disc by moving the reproducing head in thisfirst direction. It is also possible to reproduce the second video datain the reverse if the first direction after the first video data arereproduced so that similar effects to the recording format shown in FIG.13 is obtained.

In the first and second video data are encoded in accordance with MPEGstandard, the second video data should be encoded in the reverse mannerof the first video data. In such a case, it may not be possible toreproduce the second video data in the reverse direction as explainedabove. In the example of FIG. 14A also the distance of head movement isminimized, both for forward and reverse play, as the forward data groups(1F, 2F, 3F, 4F etc.) are recorded in every fourth track in a similarmanner to FIG. 13, while the reverse data groups (12R, 11R, 10R, 9R,etc.) are recorded before 2F, 3F, 4F etc. respectively, also in everyfourth track. Also the distance of the head movement is minimized at theedges of the disc as will become clear from the sequences of 6F, 7F and8F and 7R, 6R and 5R at the inside edge, and 12F, 1F and 2F, and 1R, 12Rand 11R, respectively.

FIG. 15 shows a diagram of a sequence of video data displayed on amonitor, where the sequence is obtained by using the recording formatand reading sequence shown in FIG. 14, and by receiving from and sendingto different virtual channels, respectively in order to obtain forwardand/or reverse play modes, for which purpose data are recorded in thestaggered fashion, described referring to FIGS. 13, 14 and 14A asexamples.

Multi-cast functions will be explained, referring to FIG. 16. In themulti-cast function the system manager 60 as shown in FIG. 1 alsomanages distribution of video data. If the system manager 60 receives ademand data from one or more of the end devices 40, even in the courseof service, asking to provide a same video and/or audio data astransmitted from one of SMU 20 to or requested from other end devices40, the system manager 60 outputs to the ATM switch 1 distributioncontrol data including information of the input virtual channel of theselected video data from the SMU 20 and the output virtual channel ofthe end device 40 requesting the video and/or audio data which aregenerated in response to the received demand data. For example, if anend device STB-3 requests same video data “video 1”, “video 2”, and“video3” as requested by and transmitted to another end device STB-1from the SMU 20 through an input virtual channel “vc 1” and an outputvirtual channel “vc7”, the system manager 60 outputs the updatedconversion table to the ATM switch 1, so that the header of the ATMpackets transmitting “video 1”, “video 2” and “video 3” are replaced inthe ATM switch 1 with not only the header corresponding to an outputvirtual channel “vc7” but also the header corresponding an outputvirtual channel “vc8” designated by the end device STB-3. Therefore, theATM packets containing “video 1”, “video 2” and “video 3” are suppliedto both of the end devices 40 STB-1 and STB-3 simultaneously.

The sequence of communication, shown in FIG. 17, represents a method inwhich flow of video data from a SMU 20 to a set top box 40 isestablished. First, in step 1, a user informs a set top box 40, denotedby STB, through his input device 44, that he wishes to gain access tothe system. The set top box 40 replies by asking the user in step 2 whatkind of service, like video-on-demand, games or just television, theuser wishes to select. Such selectable options may be stored in memoryof the set top box 40. Next, in step 3, the user enters his choicethrough his input device 44 to the set top box 40, which then involvesthe navigation device 30, in this figure denoted by Navi. Descriptionbelow will relate to the case, where the user has selected avideo-on-demand service menu, for which one or several navigationdevices 30 are suitable. Nevertheless, only one navigation device 30 isrepresented in this figure for clarity.

In step 5 navigation device 30 provides set top box 40 with a menu ofselectable video services, to which the navigation device 30 can gainaccess. In said menu options can also be included, referring the set topbox 40 to another navigation device 30, which can gain access to othervideo services. In the next step 6 set top box 40 passes the menu on tothe user by display thereof on monitor 43. In step 7 the user enters hischoice through his input device 44, which in this case is a request fora further menu. This request is relayed to navigation device 30 in step8, whereupon navigation device 30 supplies a new menu of selections toset top box 40 in step 9. Steps 7-10 can be repeated a number of times,until, as is the case in step 10, a menu displayed on monitor 43 by settop box 40 contains an option for a video program the user wishes toselect, which is represented by step 11. Set top box 40 in step 12requests service item provider 64, denoted by SIP, to provide for avideo stream to a top set box with a given public address, correspondingto the address of the service item provider 64. In step 13 service itemprovider 64 first request service item group 65, denoted by SIG, toprovide set top box 40 with control data necessary for optimum handlingby the set top box 40 of the video stream to be established, whichcontrol software is down-loaded into the set top box 40 in step 14. Now,set top box 40 is capable of issuing commands relating to VCR functions,where in step 15 the first play command is issued to the service itemprovider 64. In step 16 service item provider 64 locates the firstavailable video stream for the request, which in this case originatesfrom storage medium unit 40, denoted here by SMU1, and sets ATM switch1, denoted by ATM SW to connect said storage medium unit 20 and set topbox 40 by re-writing the virtual channel table in the ATM switch 1. Insteps 17 and 18 the requested video stream is routed through ATM switch1 to set top box 40, where the requested video program can now bedisplayed on monitor 43.

In FIG. 18 dynamic reconfiguration of the system is clarified. In thistiming chart on line 13 the service items group (SIG) creates a newinstance of a SMU installer and provides the number of the source SMU,of the destination SMU and other parameters. In line 14 the SMUinstaller executes a download operation to SMU1 as destination andleaves SMU1 waiting for data. In line 15 the SMU installer requests SMU2as source to start providing data to SMU1 as destination. In line 16 therequested data is transferred from SMU2 to SMU1. In line 17 SMU2 reportsto the SMU installer that the data transfer is completed. In line 18 theSMU installer informs the SIG that SMU1 is ready to serve data,whereafter the SMU installer disappears. In line b19 the SIG requestsSMU1 to start serving data to a certain virtual channel, so that suchdata can be served to end users.

In the foregoing description a number of characteristics and detailshave been described with reference to preferred embodiments. It shouldhowever be understood that the present invention is not limited to theabove description of such preferred embodiment. The requested rights aredefined by the following claims.

What is claimed is:
 1. A system for serving information data over one ormore channels to one or more end user devices, comprising: a pluralityof storage medium units for storing information data, wherein saidplurality of storage medium units include an archive storage medium unitwhich contains said information data and a plurality of delivery storagemedium units that stores said information data from said archive storagemedium unit as needed; managing means for managing distribution of theinformation data to any one of the end user devices, wherein themanaging means receives demand data relating to information dataselected through at least one respective end user device, and whereinthe managing means outputs distribution control data including channelinformation of the selected information data and routing information forsaid at least one end user device; and routing means for connecting theone or more delivery storage medium units to the at least one end userdevice, and for routing the selected information data from the deliverystorage medium units and the distribution control data from the managingmeans, wherein the managing means manages the distribution of theinformation data from one or more of said delivery storage medium unitsto an appropriate one or more of the end user device(s) in accordancewith a predetermined number representing a number of said one or moreend user devices such that the number of delivery storage medium unitsutilized is increased when the number of end user device(s) exceeds thepredetermined number, wherein said information data are divided into apredetermined number of data groups, and the information data aredivided into T (T=2,3,4 . . . ) sentences, wherein T depends on thenumber of channels, wherein the predetermined number of data groups isrecorded in the storage medium unit in such changed order that Nth(N−1,2,3,4 . . . ) data group of the last sentence of the informationdata appears after the Nth data group of the first sentence and whereinsaid routing means deliver a continuous stream of information data tothe end device by switching said data groups from the storage mediumunit between virtual channels.
 2. An information server system accordingto claim 1, wherein said routing means comprises at least one ATMswitch.
 3. An information server system according to claim 1, whereinsaid information data are video and/or audio data.
 4. An informationserver system according to claim 1, wherein said demand data include apublic address assigned to the selected information data.
 5. Aninformation server system according to claim 1, provided with controlmeans for controlling the storage medium unit according to thedistribution control data so that the storage medium unit outputs theselected information data including routing information to the routingmeans.
 6. An information server system according to claim 1, wherein themanaging means provides program data for the output of visualinformation through display means and/or audio information throughspeaker means from the storage medium units on the at least one end userdevice.
 7. An information server system according to claim 1, whereinthe managing means provides program data for information retrieval tothe at least one end user device.
 8. An information server systemaccording to claim 3, wherein said information retrieval comprises videoon demand.
 9. An information server system according to claim 1, furthercomprising: at least one second storage medium unit for storing secondinformation data and connected with the routing means wherein themanaging means comprises a table for storing data representinginformation data allocation to the first and second storage mediumunits, and wherein the managing means provides distribution control datafor the first and second storage medium units based on the demand datafrom the at least one end user device.
 10. An information server systemaccording to claim 3, wherein said one or more storage medium unitscomprise: memory means for storing video and/or audio data; table meansfor memorizing data representing a relationship between the routinginformation and the video and/or audio data stored in the memory means;program memory means for storing program data for controlling the one ormore storage medium units; and at least one interface for transmittingthe video and/or audio data with the routing information and a controlsignal in one or more packets to the routing means and for receiving theprogram data in one or more packets from the routing means.
 11. Aninformation server system according to claim 10, wherein said routinginformation relates to one or more virtual channels and said interfaceis an ATM interface.
 12. An information server system according to claim10, wherein said at least one interface receives control datarepresenting a selected operation mode for the at least one end userdevice and wherein the controller controls the memory means according tothe received control data so that the information data is reproducedfrom the memory means in the selected operation mode.
 13. An informationserver system according to claim 12 wherein said operation modecomprises still mode, fast forward mode, reverse mode and/or mosaicmode.
 14. An information server system according to claim 3, whereinsaid video and/or audio data is divided in a predetermined number ofdata groups, wherein the predetermined number of data groups is recordedin a sequence different from an original sequence on a recording mediumin said one or more storage medium units and wherein said routing meansdelivers continuous video and/or audio data to the at least one end userdevice by switching said data groups from said one or more storagemedium units to said one or more end user devices.
 15. An informationserver system according to claim 14, wherein said recording medium is anagile disk and wherein a first portion of said data group is recorded onevery N-ths (N=1,2,3 . . . ) track of the disk, and remaining portionsof said data groups are recorded on remaining tracks of the disk.
 16. Aninformation server system according to claim 15, wherein the firstportion of said data groups is reproduced by moving a head in a firstdirection and the remaining portion of the data groups is reproduced bymoving the head in a second direction opposite to the first direction.17. An information server system, for serving information datacomprising video and/or audio data over one or more channels to one ormore end user devices, comprising: one or more storage medium units forstoring information data selectable by a respective end user device,wherein each storage medium unit includes a controller for controlling aplay mode of said information data stored; managing means for managingdistribution of the information data to any one of the end user devices,wherein the managing means receives demand data relating to informationdata selected by the user through a respective end user device, andwherein the managing means outputs distribution control data includingchannel information of the selected information data and routinginformation for said end user device; wherein said controller controlsthe play mode of a respective storage medium unit in accordance withsaid distribution control data; routing means for connecting the storagemedium unit to the end user device, and for routing the information datafrom the storage medium unit and the distribution control data from themanaging means; and wherein said video and/or audio data are dividedinto a predetermined number of data groups, and the video and/or audiodata are divided into T (T=2,3,4 . . . ) sentences, wherein T depends onthe number of channels, wherein the predetermined number of data groupsis recorded in the storage medium unit in such changed order that Nth(N=1,2,3,4 . . . ) data group of the last sentence of the video dataappears after the Nth data group of the first sentence and wherein saidrouting means deliver a continuous stream of video data to the enddevice by switching said data groups from the storage medium unitbetween virtual channels.
 18. A system for serving information data overone or more channels to one or more end user devices, comprising: aplurality of storage medium units for storing information data, whereinsaid plurality of storage medium units include an archive storage mediumunit which contains said information data and a plurality of deliverystorage medium units that stores said information data from said archivestorage medium unit as needed; managing means for managing distributionof the information data to any one of the end user devices, wherein themanaging means receives demand data relating to information dataselected through at least one respective end user device, and whereinthe managing means outputs distribution control data including channelinformation of the selected information data and routing information forsaid at least one end user device; and routing means for connecting theone or more delivery storage medium units to the at least one end userdevice, and for routing the selected information data from the deliverystorage medium units and the distribution control data from the managingmeans, wherein said managing means selects a special play mode forsupplying an altered sequence of scenes to the at least one end userdevice by switching channels for supplying the data information to theat least one end user device, wherein said information data are dividedinto a predetermined number of data groups, and the information data aredivided into T (T=2,3,4 . . . ) sentences, wherein T depends on thenumber of channels, wherein the predetermined number of data groups isrecorded in the storage medium unit in such changed order that Nth(N=1,2,3,4 . . . ) data group of the last sentence of the informationdata appears after the Nth data group of the first sentence and whereinsaid routing means deliver a continuous stream of information data tothe end device by switching said data groups from the storage mediumunit between virtual channels.
 19. A system for serving information dataover one or more channels to one or more end user devices, comprising: aplurality of storage medium units for storing information data, whereinsaid plurality of storage medium units include an archive storage mediumunit which contains said information data and a plurality of deliverystorage medium units that stores said information data from said archivestorage medium unit as needed; managing means for managing distributionof the information data to any one of the end user devices, wherein themanaging means receives demand data relating to information dataselected through at least one respective end user device, and whereinthe managing means outputs distribution control data including channelinformation of the selected information data and routing information forsaid at least one end user device; and routing means for connecting theone or more delivery storage medium units to the at least one end userdevice, and for routing the selected information data from the deliverystorage medium units and the distribution control data from the managingmeans, wherein said managing means selects a special play mode forsupplying a mosaic of scenes to the at least one end user device byselecting scenes from different channels, wherein said information dataare divided into a predetermined number of data groups, and theinformation data are divided into T (T=2,3,4 . . . ) sentences, whereinT depends on the number of channels, wherein the predetermined number ofdata groups is recorded in the storage medium unit in such changed orderthat Nth (N=1,2,3,4 . . . ) data group of the last sentence of theinformation data appears after the Nth data group of the first sentenceand wherein said routing means deliver a continuous stream ofinformation data to the end device by switching said data groups fromthe storage medium unit between virtual channels.
 20. An informationserver system according to claim 1, further comprising navigation meansfor providing in a predetermined sequence menus which describe saidinformation data.
 21. An information server system according to claim20, wherein said navigation means outputs to a respective end userdevice a software program for driving said respective end user device toselect said menus in accordance with said predetermined sequence.
 22. Aninformation server system according to claim 1, wherein saiddistribution control data is in the form of a software program; whereinsaid managing means downloads said software program to said respectivestorage medium unit.
 23. An information server system according to claim1, wherein said one or more storage medium units includes an archivestorage medium unit for archiving a plurality of distribution controldata output by said managing means.
 24. An information server systemaccording to claim 23, wherein said one or more storage medium unitsinclude a delivery storage medium unit for storing said information dataselected through the respective end user.
 25. An information serversystem according to claim 1, wherein said one or more storage mediumunits store the information data according to said estimate data.
 26. Asystem for serving information data over one or more channels to one ormore end user devices, comprising: a plurality of storage medium unitsfor storing information data, wherein said plurality of storage mediumunits include an archive storage medium unit which contains saidinformation data and a plurality of delivery storage medium units thatstores said information data from said archive storage medium unit asneeded; managing means for managing distribution of the information datato any one of the end user devices, wherein the managing means receivesdemand data relating to information data selected through at least onerespective end user device, and wherein the managing means outputsdistribution control data including channel information of the selectedinformation data and routing information for said at least one end userdevice; and routing means for connecting the one or more deliverystorage medium units to the at least one end user device, and forrouting the selected information data from the one or more storagemedium units and the distribution control data from the managing means,wherein said distribution control data further includes backup controldata for assigning one of said one or more delivery storage medium unitsto supply the selected information data when another of said one or moredelivery storage medium units for supplying the selected informationdata is malfunctioning, wherein said information data are divided into apredetermined number of data groups, and the information data aredivided into T (T=2,3,4 . . . ) sentences, wherein T depends on thenumber of channels, wherein the predetermined number of data groups isrecorded in the storage medium unit in such changed order that Nth(N=1,2,3,4, . . . ) data group of the last sentence of the informationdata appears after the Nth data group of the first sentence and whereinsaid routing means deliver a continuous stream of information data tothe end device by switching said data groups from the storage mediumunit between virtual channels.
 27. An information server systemaccording to claim 26, wherein said one or more storage medium unitsstore the information data according to said backup control data.
 28. Aninformation server system according to claim 27, wherein said managingmeans manages distribution of the information data according to saidbackup control data.